Multipliers are commonly used in a wide variety of electronic devices to shift one or more frequencies to a different value. In many applications, a local oscillator (“LO”) signal may be generated for down conversion of a received RF signal. Examples include digital broadcast system (DBS) tuners or receivers, cable modem tuners, and a variety of devices operating within wireless communication systems such as a cellular telephones, cordless telephones, wireless handsets, mobile stations, pagers, and the like. In these and other applications, the received RF signal usually takes a form of a carrier signal at a carrier frequency that is modulated by an information signal at a baseband frequency. As the baseband frequency is typically much lower than the carrier frequency, a receiver must translate or down convert the carrier frequency of the RF signal down to the baseband frequency in order to extract the baseband information from the signal.
In some systems, the frequency of the RF signal may first be converted to an intermediate frequency (IF) and the IF may then be converted to the baseband frequency. In some other systems, which are referred to as direct translation or direct conversion systems, the RF frequency is converted directly to the baseband frequency. Direct conversion systems may be advantageous in that the IF stage is eliminated, thereby reducing the cost and size of communication devices incorporating the systems. Multipliers implemented in power detection circuits, analog demodulators, zero-IF receiver front-ends, and the like, may encounter an intended output signal that is located near DC (zero Hertz), which may be located in the same frequency range as a low-frequency noise generated by the multiplier.
Thus, it is with respect to these considerations and others that the present invention has been made.